Furnace.



No. 645,3I9. Patented Mar. l3, I900. W. C. JOHNSON.

FURNACE.

\Apglication filed Feb 23, 1899. v (No Model.)

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UNITED STATES PATENT \VILLIAM OUMMING JOHNSON, OF MEMPHIS, TENNESSEE.

' FURNACE.

SPECIFICATION-forming part of Letters Patent No. 645,319, dated March 13, 1900.

Application filed February 23, 1899. Serial No. 706,577. (No model.)

To ail whom it may concern.-

Be it known that I, WILLIAM CUMMING JOHNSON, of Memphis, in the county of Shelby and State of Tennessee, have invented a new and Improved Furnace, of which the following is a full, clear, and exact description.

The purpose of this invention is to provide a furnace in which the smoke will be entirely consumed, which end is attained by the introduction into the furnace directly over the fire of a volume of atmospheric air, this introduction of air being so controlled that the supply of air is automaticallycut off when the conditions within the furnace render such supply of air no longer necessary.

This specification is the disclosure of one form of my invention, while the claims define the actual scope thereof.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure 1 is a side elevation of my invention. Fig. 2 is a vertical section taken through the fire-box of the furnace, showing my invention applied; and Fig. 3 is a plan View of the fire-box with parts of the furnace iii section and parts displaced to better illustrate the structure of the parts shown.

The furnace is constructed with the bridgewall 4, formed with a transverse passage 5 therein, the passage having a contracted upper portion extending along the upper edge of the bridge-wall and having communication with the atmosphere at one side of the furnace, the open end of the passage being closed by a door 6. (See Fig. 1.) Erected in the fire-box above the grate and disposed in an inclined plane running forwardly and upwardly from the top edge of the bridge-wall are a number of bends of pipe 7, the ends of which project outside of the furnace. These pipes are fed with water by a tube 8 (see Fig. 1) and discharge into the boiler by the pipes 9, the pipes S and 9 being located outside of the furnace. The ends of the pipes 7 are provided with plugs 10, by which the pipes may be opened for the purpose of cleaning the same. Carried on the upper sides of the pipes 7 within the fire-box is a continuous partition 11, of fire-brick, which closes the spaces between the pipes and forms an imperforate wall over the grate and terminates slightly below the boiler 12, so that the draft upon striking the under side of this inclined wall will pass along the same and around the upper edge thereof. In Fig. 2 the fire-brick partition 11 is shown, but in Fig. 3 it is omitted to better illustrate the pipes 7. The supply of air passing through the passage 5 will be uniformly distributed along the lower edge of the wall formed by the pipes 7 and firebrick 11, and this air will pass along the under side of the wall referred to directly over the fire on the grate-bars, causing complete combustion within the fire-box, and consequently consuming all of .the smoke that passes from the unburned fuel.

It is known that in furnaces when the fuel has been partly consumed the fire no longer emits smoke. It is only when the fire is newly stoked that smoke escapes, which is due to the fact that there is not sufficient oxygen supplied to the furnace to eifect complete combustion in the firebox. Now it is the purpose of my invention to supply an additional quantity of oxygen whenever the furnace is stoked, thus providing the necessary oxygen at this period, andto cutoff the additional supply of air at a predetermined time after the stoking, so as to avoid permanent increase of the supply of air, which after such time would onlyhave the effect of cooling the furnace. This is effected by means of a flexible connection 14:, connected with the firedoor 15 of the furnace and passed over an idler-pulley 16, from which it extends rearwardly along one side of the boiler around two pulleys 17 to a weight 18. This weight 18 has a second flexible connection 19 attached thereto, which in turn is connected with and controls the valve 20 of an ordinary flushing-tank 21. Arranged in the flushingtank is a float 22, the lever 23 of which is connected with a third flexible connection 24, which passes down to and has connection with the door 6. The weight 18 is kept normally raised by the door 15 when such door is closed, and when the door is opened the weight drops to raise the valve 20 and discharge the water from the tank 21. As the water falls in the tank the float 22 drops, and through the medium of the lever 23 and connection 24 the door 6 is raised. lVith such gen.

an apparatus when the fire-door 15 is closed the door 6 is closed and the additional volume of atmospheric air, or, in other words, oxygen, is not supplied to the furnace through the passage 5; bntshonld the door be opened to stoke the furnace the weight 18 is dropped, as shown in Fig. 1, and the valve 20 is raised. Immediately the water drops from the tank 21, and the falling of the float 22 in the tank opens the door 6, thus permitting the air to move through the passage 5 and into the furnace to supply the additional volume of oxy- The furnace may then be stoked and the door 15 closed, which will have the effect of raising the weight 18 and returning the valve 20 toits closed or seated position. Then the water will again rise in the tank 21, cansing the float22 to rise. This return of the water to the normal height in the tank 21 will consume a certain amount of time, during which it is calculated that the door 6 shall remain open, and the additional volume of air will then be supplied to the furnace without interruption. When, however, the water in the tank has been restored to its normal level, the float 22 will be raised and the door 6 dropped to closed position. It will thus be seen that by the apparatus I provide the furnace is supplied with an extraordinary quantity of air for a short time after each period of stoking, so that the fuel thrown in at the stoking will have the necessary oxygen to effect its complete combustion; but when the gases and smoke of the fuel have been burned the air will be shut off from the passage 5 and the furnace will resume its operation as under the ordinary conditions until it again becomes necessary to stoke the furnace, when this operation will be repeated.

My apparatus gives the greatest supply of air immediately after fresh firing, when it is most needed, and then gradually diminishes with the gradual consumption of all the smoke-producing qualities of the fuel. The flames must pass under the pipes 7 to the boiler, which thus affords a heating-surface that works a great saving in the steaming of the boiler and economy of coal consumption. The pipes 7 are so connected with the boiler that they will never fail of a supply of water. The constant circulation of the feed-water through these pipes will keep them from burning out, and there is no danger of their failin g to support the light fire-brick covering 11. It is further to be observed that the apparatus is entirely automatic in its operation and is not dependent upon the care of the fireman, whose work is exactly as in the old form of furnace. The automatic regulation of the draft from the flue 5 prevents the cooling down of the furnace, which would otherwise result should the extra draft be kept up long after the stoking operation.

Various slight changes might be made in the details of my invention without departing from the spirit thereof or limiting its scope, and hence I do not wish to limit myself to the precise details of construction herein set forth.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. In afurnace,the combination of abridgewall having a passage therein communicating with the atmosphere and discharging into the fire-box, a closure for said passage, a fire-door, a water-tank comprising a valve commanding the tank, and a .float sustained by the water in the tank and commanding the water-supply, a connection between the float and the closure, and a connection between the valve and the fire-door.

2. A furnace having a passage therein for supplying atmospheric air to the furnace, a closure for said passage, a fire-door, a watertank comprising a valve and a float, the float commanding the water-supply, a connection between the closure and the float, and a connection between the fire-door and the valve.

3. In a furnace, the combination with the feed and draft doors, of a water-tank, a valve commanding the water-tank, a weight having connection with the valve to raise the same, a connection between the weight and the feeddoor to raise the weight, as the feed-door is opened, a float mounted in the tank and commanding the water-supply, and a connection between the float and the draft-door.

WILLIAM. CUMMING JOHNSON. 

